Finding the North Magnetic Pole is no easy task. The first person to reach the
elusive pole was James Clark Ross in 1831. When his uncles ship became trapped
in ice off the northwest coast of Boothia Peninsula, Ross took magnetic measurements
and found the pole. Roald Amundsen headed to the Arctic 70 years later to set
up a temporary magnetic observatory to relocate the pole. In the century since,
only a handful of others have made it to the North Magnetic Pole. Even now, tracking
its movement is a challenge.

In May 2001, Larry
Newitt of the Canadian Geological Survey and his French and Canadian team took
the challenge. It was Newitts fourth time since 1974 flying in a Twin Otter
plane from Resolute Bay to the frozen Arctic Ocean to survey the North Magnetic
Pole. It was geophysicist Mioara Mandeas first, and the first time a woman
had ever joined the expedition. We have really a very short window to do
these measurements, she explains. In the remote Canadian Arctic, the sun
must be shining. The ocean must still be frozen, allowing the team to land on
the ice. And the day should be geomagnetically quiet, with few solar storms. The
pole moves a lot in a normal day. So if there are some external disturbances,
or magnetic storms, its really much more difficult to catch it, says
Mandea of the Institut de Physique du Globe de Paris.

The North Magnetic Pole has moved 1,300
kilometers northwest since James Clark Ross first reached the pole in 1831. At
its current trajectory and newly calculated speed of 40 kilometers per year, the
North Magnetic Pole will reach Siberia by the year 2050. The Canadian Geological
Survey, the Institut de Physique du Globe de Paris and the Bureau de Recherches
Géologiques et Minières collaborated on the latest survey to the
North Magnetic Pole. Image by
Larry Newitt

While solar activity creates daily changes in the poles position, the main
source of Earths magnetic field lies within its convecting liquid iron core.
Activity from the outer core creates variations on longer time scales  so
called secular variation that causes the pole to move slowly across the Arctic.

The team measured the declination  the angle between true geographic north
and magnetic north  and the inclination, or angle between the horizontal
and the direction of Earths magnetic field, as well as the total field intensity.
And the pole is the spot where the inclination is, in the case of the magnetic
field, pointing straight down. We cant ever really hope to observe at the
exact location of the pole, so we surround it and then use all the observations
to eventually interpolate it, Newitt says. They located the North Magnetic
Pole about 966 kilometers from the geographic North Pole.

The expedition, Newitt says, was routine, but they did see a large acceleration
over the last decade in the poles movement. Its moving at about
40 kilometers per year and roughly northwest. If it keeps going in that direction
for another 50 years or so, itll end up off the coast of Siberia,
he says.

Newitt and his colleagues last surveyed the pole in 1994, and noticed an acceleration.
They decided to return in 1998, six years earlier than when they would usually
head back. But inclement weather prevented the team from landing. The following
year, they were only able to make a few observations. But in 2001, they made it,
completing a survey three years in the making. And sure enough, the pole
has really taken off over that interval of time. Prior to the 1994 survey, it
had been going at around 10 kilometers per year. We had noticed it speeding up
to about 15 in 1994 and now its at around 40, Newitt says.

Why it has sped up so much, researchers still do not know. But Newitt and Mandea
both believe the changes are linked to sudden changes in the secular variation
of Earths magnetic field. Also called geomagnetic jerks, these
sudden increases in the magnetic fields intensity occur over periods of
time lasting from months to a year or two. Mandea says that in the last century,
researchers have recorded four jerks of global extent  in 1969, 1978, 1992
and 1999/2000.

You see all these very clearly in the data from the Resolute Bay Magnetic
Observatory. And each time that one of these jerks occurs, the change in the magnetic
field at Resolute gets faster. And so I believe that the acceleration of the magnetic
pole is most likely related to a series of geomagnetic jerks, Newitt says.

Geomagnetic jerks and the movement of the North Magnetic Pole both originate from
changes in Earths fluid outer core. We think that they are linked
with the motion in the outer core, but there is no physical explanation for this
observation, Mandea says. Indeed, the current scientific understanding of
processes at the core-mantle boundary is a tenuous one.

We are not really able to track the movements of the poles to sufficient
resolution in time to distinguish individual events such as geomagnetic jerks,
partly because of the hostile environment for making observations and partly because
models of the Earths magnetic field have difficulty in resolving jerks,
says Susan Macmillan of the British Geological Survey. She says that many researchers
place too much significance on the magnetic poles for determining what is happening
in the fluid core.

Mandea is working to establish a quantitative connection between the poles
movement and the geomagnetic jerks. In a paper published in last months
Nature, Mandea and colleagues used MAGSAT and ORSTED satellite data for
1980 and 2000 to describe changes in the magnetic field at a global scale. And
its very clear that in the Northern Arctic theres a very high secular
variation and its nearly the same in the region centered on southern Africa,
but very different in the Pacific area. She believes this may be the key
to understanding the connection.

In the meantime, though, Mandea says the survey is an important part of drawing
declination maps for navigators and scientists who study geomagnetism. An international
team of scientists produces geomagnetic models and maps. And while the poles
position is not directly involved, its good information to verify that our
models are good enough at the very high latitudes, she says.

Newitt hopes to return to the pole soon. And he adds that even if the North Magnetic
Pole leaves Canadian territory, his work will continue. Itll move
north of Alaska, but much further from mainland Alaska than it is from the Canadian
Arctic islands, so it will still be more accessible for us than for anyone in
Alaska. The worst thing that could happen is that itll get so remote that
no one can get to it.